Drinking eight cups or two litres of wat

题型:阅读理解

问题:

Drinking eight cups or two litres of water a day is longstanding advice. But is there any scientific basis for it, asks Dr Chris van Tulleken.

You know those ads that remind us that even a small drop in hydration(水合作用) levels can massively affect performance so you need to keep hydrated with whatever brand of super drink they're selling?

They seem pretty scientific don't they? Man in white coat, athlete with electrodes attached and so on. And it's not a hard sell because drinking feels right - you're hot and sweating so surely replacing that fluid must be beneficial.

Well earlier this year sports scientists in Australia did an extraordinary experiment that had never been done before.This group wanted to find out what happened to performance after dehydration. So they took a group of cyclists and exercised them until they lost 3% of their total body weight in sweat.

Then their performance was assessed after rehydration with either 1) nothing, 2) enough water to bring them back to 2% dehydration or 3) after full rehydration.

So far nothing unusual, but the difference between this and almost every other study that's ever been done on hydration was that the cyclists were blind to how much water they got. The fluid was given intravenously without them knowing the volume.

This is vital because we all, and especially athletes, have such an intimate(密切的)psychological relationship with water consumption.

Remarkably, there was no performance difference between those that were fully rehydrated and those that got nothing. This study was part of a growing movement to "drink to thirst" which hopes to persuade athletes not to over hydrate with the potentially fatal consequence of diluting your sodium level, causing hyponatraemia.

Perhaps the result shouldn't be so surprising. Humans evolved doing intense exercise in extreme heat and dryness. We are able to tolerate losses in water relatively well whereas even slight over hydration can be far more dangerous. In simple terms, being too watery is as bad for you as being too concentrated.

小题1:What’s the main idea of the passage?

A.There is no scientific basis for drinking eight cups of water a day

B.People used to drink eight cups of water a day

C.An experiment about whether people should drink eight cups of water.

D.People shouldn’t believe longstanding advice.小题2:what does the word“dehydration ”in paragragh 4 mean?

A.doing exercise

B.losing water

C.drinking water

D.having a rest小题3:What is NOT TRUE according to the passage?

A.Drinking too much water is bad for us

B.Sports scientists in Australia did an extraordinary experiment for the first time.

C.Those that were fully rehydrated and those that got nothing performed differently.

D.The cyclists didn’t know how much water they got.小题4:What can we learn from the last paragragh?

A.Humans can bear losing water relatively well

B.It’s dangerous to drink water.

C.Athletes should drink more water than others.

D.This study was part of a growing movement to "drink to thirst".小题5:what is Dr Chris van Tulleken’s attitude towards the. longstanding advice?

A.positive

B.doubtful

C.supportive

D.indifferent

考点:健康环保类阅读
题型:阅读理解

右心室心肌梗死的处理包括()

A.不宜用利尿剂

B.硝酸甘油

C.利多卡因

D.扩张血容量

E.低血压时优选多巴酚丁胺

题型:阅读理解
阅读理解。
人类能在地球上生活多久(节选)
       ①人类能在地球上生活多久?这既涉及可持续发展战略,涉及地球为人类的生存和发展所提供的资源,也涉及地球的外在环境究竟能在多少年内维持不变。
       ②太阳是决定地球外在环境最重要的因素。根据近代天文学家的理论,太阳将持续而稳定地向地球提供光和热,地球绕太阳旋转的平均半径,将长期维持不变,至多只有极小的摆动,这一过程将至少还持续40亿年。过了40亿年后,太阳将逐渐膨胀而演化为红巨星,最后将地球完全吞吃到它的“肚子”里。
       ③太阳对地球的影响实在是太巨大了,“只要太阳吼一吼,地球立即抖一抖”。至于人类,却承受不了地球的任何抖动!不过,太阳为地球持续提供长达4000万年的光和热却是没有问题的,因为在4000万年的年代里,所消耗的能量还不到太阳总量的1%!所以,研究人类在地球上持续生存和发展的问题,至少要以人类能在地球上持续生存4000万年为奋斗目标!
       ④但是人类面临的真正威胁,却是来自人类自身。如果人们认为400年前伽里略是近代科学之父的话,那么这400年来科学、技术以及工业、农业的发展,就远远超过自有人类历史以来的400万年间的成就。与此同时,近400年来所消耗的地球上的资源,也大大超过了在400万年间人类所消耗的资源总量!如果按照现在消耗不断增长的趋势发展下去,试问4000年后乃至4000万年后的地球将是什么样的面貌?
       ⑤地球上的资源可分为两类:一类是可再生资源,另一类是不可再生资源。虽然人类可以用消耗可再生资源的办法补充一些不可再生资源,但这在数量上毕竟是有限度的。所以,人类的生存和发展的问题,归根结底将取决于地球上的资源能在多少年内按照某些资源的消耗标准维持人类的正常生活。
       ⑥其实,4000万年只是一个保守的说法,太阳的光和热,完全可能持续更长一些时间,即使太阳系内出现某些反常事件,如小行星撞击地球,但也不太可能在4000万年内发生,而且人们完全能发射有超强破坏力的导弹,使小行星改变航道。所以,地球上的居民,至少在相当长的一个时期内,是大可不必“杞人无事忧天倾”的!
       ⑦但是,真正值得忧虑的,是人,是人能否控制人类自身!
1.本文从两个方面回答了“人类能在地球上生活多久”的问题,一个方面是太阳能否持续而稳定地向地
     球提供光和热,另一个方面是______________________
2.第③段中,说,“太阳为地球持续提供长达4000万年的光和热却是没有问题的”。他这样说的根据是
     什么?
     答:                                                                                                                  
3.第④段中,作者说,“但是人类面临的真正威胁,却是来自人类自身”。“来自人类自身”的威胁指
     什么?
     答: ________________                                                                                   
4.按要求分析下列句子中加线的词语。
   (1)这一过程将至少还持续40亿年。“这一过程”指什么?答:_________________________ 
   (2)但是,真正值得忧虑的,是人,是人能否控制人类自身!说说“控制人类自身”的含义。
            答:_______________________                                                         。
5.读本文后,你学到了哪些知识?请列出两条。
    (1)______________________ (2)_______________________
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施工起重机械和整体提升脚手架在使用前,施工单位应当组织产权(生产、租赁)单位、安装单位的安全、设备管理人员和其他技术人员参加验收。

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C.710kW;51A

D.700kW;49.5A

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